There is a national interest in the discovery of alternative sources of fuels and chemicals that are not derived from petroleum resources. As the public discussion concerning the availability of petroleum resources and the need for alternative sources continues to grow, it is anticipated that future government mandates will require transportation fuels to include, at least in part, hydrocarbons derived from sources besides petroleum. As such, there is a need to develop alternative sources for hydrocarbons useful for producing fuels and chemicals.
One possible alternative source of hydrocarbons for producing fuels and chemicals is the natural carbon found in plants and animals, such as for example, oils and fats. These so-called “natural” carbon resources (or renewable hydrocarbons) are widely available, and remain a target alternative source for the production of hydrocarbons.
It is known that oils and fats can be processed and used as fuel. “Bio Diesel” is one such product and may be produced by subjecting a base vegetable oil to a transesterification process using methanol in order to convert the base oil to desired methyl esters. After processing, the products produced have very similar combustion properties as compared to petroleum-derived hydrocarbons. However, the use of Bio-Diesel as an alternative fuel has not yet been proven to be cost effective. In addition, Bio-Diesel often exhibits “gelling” thus making it unable to flow, which limits its use in pure form in cold climates.
U.S. Pat. No. 7,550,634, which is herein incorporated by reference in its entirety, describes a process for the conversion of biomass derived oils or fatty materials such as triglycerides, diglycerides, monoglycerides, and free fatty acids into diesel fuel range hydrocarbons using a refinery hydrotreater. In this technology, triglycerides (oils/fats) are hydrotreated to remove the oxygen from the triglycerides molecule to produce the linear hydrocarbons (also named as renewable diesel).
It is also known that biomass carbohydrates can be processed and used as fuel. Biomass carbohydrates and other sugar-based feedstocks have been used to produce ethanol, which has been used in gasohol and other energy applications.
U.S. Pat. No. 7,678,950, which is herein incorporated by reference in its entirety, describes a process for converting biomass (such as carbohydrates, starches, lignins, and other biomass) into gasoline range hydrocarbons (also named as renewable gasoline). In this technology, cellulose and hemicellulose (e.g. carbohydrates, starches, and lignins) as two major constitutes in the biomass may be broken down to C6 and C5 sugars (e.g. glucose, lactose, fructose, sucrose, and dextrose) using for example acid or enzyme hydrolysis processes. The carbonyl groups of C6 and C5 sugars can be further catalytically hydrogenated to produce a polyalcohol including sorbitol (C6H14O6) sugar alcohols using a commercial process. It was demonstrated that the sugar alcohols, such as sorbitol, can be further hydrogenated to C6 hydrocarbons (renewable gasoline) using a hydrotreating process. In addition, ZSM-5 zeolite catalyst has also been used to convert a sorbitol/water/isopentane mixture to gasoline hydrocarbons (US2007142633, incorporated by reference in its entirety).